A manufacturing process for a semiconductor device can include a silicidation process of forming a silicide to reduce contact resistances between a gate and source/drain regions and contacts thereon and/or thereover. To detect a defect in the silicidation process, monitoring techniques can be used, such as transmission electron microscope (TEM) analysis for a silicide layer and a method of measuring a contact resistance. TEM analysis is a destructive test which requires sacrificing a wafer and takes a long time for conducting analysis while only monitoring a partial region. Moreover, in the method of measuring a contact resistance, only a region receiving the contact can be monitored. A defect in the contact resistance generated in a source/drain implantation process cannot be detected. In order to monitor a silicide for a poly gate, a contact-forming process can be performed before measuring a contact resistance with respect to a metal interconnection layer. Accordingly, since subsequent processes should be performed, ranging from a process of patterning a poly gate to a process of forming a metal interconnection layer, it can be difficult to perform a monitoring process according to various measurement items. Also, when a resulting semiconductor device throughout the processes has a defect, it should be discarded, thus increasing manufacturing costs.